It has been a deadly long weekend, with four people having lost their lives and others seriously injured.
All of the collisions took place Saturday evening.
The first occurred shortly before 8 p.m. on Fairgrounds Road in Clearview Township, west of Barrie.
The initial investigation reveals the vehicle entered the ditch and the driver was ejected.
A 46-year-old from Clearview Township was pronounced dead at the scene.
Shortly before 10 p.m., Nottawasaga OPP and emergency crews were called to a serious single-vehicle collision on County Road 1.
Early reports from the investigation reveal that the driver lost control of the vehicle before a sharp curve. The vehicle entered the ditch and rolled, coming to rest on its roof.
The 60-year-old male driver from Mono suffered a non-life-threatening injury while his 82-year-old female passenger, also from Mono, was pronounced dead at the scene.
The third collision was another in Clearview Township, shortly before 11 p.m.
A Ford Mustang was passing numerous vehicles on Highway 26 when it collided head-on with a Chevrolet Blazer, according to police.
The 20-year-old man driving the Mustang sustained serious injury and was taken to an area hospital.
The passengers in the Mustang, a 20-year-old man and a 19-year-old woman, were both pronounced dead at the scene.
The driver of the Chevy Blazer suffered serious injuries and was transported to a Toronto-area trauma centre.
In all cases, the roads were shut down for some time as OPP members trained in collision reconstruction measured, photographed and collected evidence.
Names of the deceased individuals are being withheld until next-of-kin can be notified.